BBC News110308: Plans for a possible no-fly zone over Libya are gathering pace in response to air strikes against rebel-held areas by Libyan leader Col Gaddafi.

The UK and France are drafting a UN resolution for an air exclusion zone and the issue is due to be debated by Nato defence ministers on Thursday.

Gulf Arab states have already backed the idea.

However, the BBC’s Barbara Plett at the UN says the international community is divided over the issue.

The debate comes as forces loyal to Col Gaddafi have launched counter-strikes against rebels, checking their recent advances.

In another development, unconfirmed reports said Col Gaddafi had sent a message to the rebels, offering to step down on condition he and his family were allowed to leave Libya safely with their wealth intact.

The rebel leadership in Benghazi – which calls itself the Transitional National Council – is said to have rejected the offer.

The prospect of a no-fly zone gathered pace after Gulf states supported the idea and also called for an urgent meeting of the Arab League. They have condemned the use of violence against civilians by Libyan government forces.

UK Foreign Secretary William Hague said Britain was working “with partners on a contingency basis on elements of a resolution on a no-fly zone”.

But he spelled out conditions attached to any such move.

Arab and African support would be crucial, he said, and there would need to be a clear trigger – most likely a sharp worsening of conditions for civilians.

Mr Hague also said the move needed the legal backing of a UN resolution – an element also required by the US and Nato.

Nato Secretary-General Anders Fogh Rasmussen also stressed the need for UN authorisation for any no-fly zone, adding: “I can’t imagine the international community and the United Nations would stand idly by if Gaddafi and his regime continue to attack their own people.

“We have asked our military to conduct all necessary planning so that we stand ready at short notice.”

The US said on Monday it was still considering a possible military response to the situation in Libya, along with its allies.

White House spokesman Jay Carney said arming rebel groups was “one of the range of options that is being considered”, but stressed that Washington was still evaluating those groups opposed to Col Gaddafi.

US Defence Secretary Robert Gates said the Pentagon had prepared a number of military options for President Obama, but added: “I think at this point there is a sense that any action should be the result of an international sanction before anything is done.”

On the ground in Libya, pro-Gaddafi forces launched several air strikes on the rebel-held oil port of Ras Lanuf on Monday.

Further to the west, Bin Jawad has fallen to forces loyal to the Libyan leader.

Correspondents say rebels fought off a strong counter-offensive as Gaddafi forces attacked towns near Tripoli and also in the east.

As the fighting intensifies, fears of a humanitarian crisis along Libya’s borders are growing.

The UN’s emergency relief co-ordinator, Valerie Amos, said that up to one million foreign workers – who have either just left Libya or are still trapped there by the recent fighting – will need emergency aid in the coming weeks.

She said that $160m (£98m) was needed for camp management, food, nutrition, health care, water, sanitation and hygiene.

Unconfirmed reports of an offer made by Col Gaddafi to the rebels were made by Al-Jazeera and two Arab newspapers.

The London-based daily Asharq al-Awsat said the Libyan leader had sent a negotiator to Benghazi at the weekend saying he was ready to abandon power and leave, in return for assurances on his safety, that of his family, and his wealth.

Al-Jazeera said sources from the transitional council told its correspondent in Benghazi that the offer was rejected because it would have amounted to an “honourable” exit for the Libyan leader.